Adrenocorticotropin alpha- and beta-melanocyte stimulating hormones, and the opiate peptide, beta-endorphin are hormones with markedly different biological activity yet they are synthesized from a common precursor proteins in the anterior and intermediate lobes of the pituitary. Although the two lobes start with similar forms of the precursor they process these forms to different end products. A major research objective is to elucidate the mechanisms of regulation of production of these hormones in two lobes of the pituitary. A mouse pituitary tumor cell line (AtT-20/D16v cells) will be used initially as a model system for studying expression of the gene for the common precursor because this cell line mimics the behavior of anterior pituitary cells in culture. Our aim is to define the proteolytic and glycosylation steps involved in processing and release of the component hormones of the precursor. Similar studies will be done with monolayer cultures of cells - from the lobes of mouse and rat pituitary. The effect of glucocorticoids, hypothalamic releasing factors, and other regulators on processing and release of ACTH and Beta-endorphin will be tested in these cultures systems. To determine if the precursor proteins in the anterior and intermediate lobes of the pituitary have different amino acid sequences, the mRNA that codes for the precursor will be isolated from the lobes, characterized, and transcribed into complementary DNA (cDNA). The cDNA will be cloned in bacteria and the nucleotide sequence of the cloned DNA will be determined.